Thermoplastic bags for diverse use, such as sandwich bags, garbage bags, leaf bags and the like, are produced by extruding a tube of thermoplastic material, such as high density polyethylene, with the resulting tubularly-formed material being cooled, heat sealed and either scored or cut to the desired length. The thus formed bag exhibits a strip tensile breaking length representative of the processed thermoplastic material. The end use of the thermoplastic bag normally dictates the selection of the thermoplastic material, e.g. as a sandwich bag, a low porosity and normal strength thermoplastic material is selected whereas a garbage bag would require the selection of a thermoplastic material exhibiting high strength characteristics.